Answer
P is preceding numberof \[EC{{5}_{sixteen}}\].
\[\begin{align}
& P=EC{{5}_{sixteen}}-1 \\
& =EC{{4}_{sixteen}}
\end{align}\]
F is following number of \[EC{{5}_{sixteen}}\]
\[\begin{align}
& F=EC{{5}_{sixteen}}+1 \\
& =EC{{6}_{sixteen}}
\end{align}\]
